https://devzone.nordicsemi.com/f/nordic-q-a/11801/received-a-sigtrap-trace-breakpoint-trapHi We use the nRF51822 with s110 active. As long the s100 isn&#39;t active, we can debug, set breakpoints, stop, continue like it should work. When activating the s110 and communicate via ble interace, each time we run into a breakpoint and try to stepen-USTelligent Community 13Tue, 09 Feb 2016 12:03:13 GMThttps://devzone.nordicsemi.com/thread/44615?ContentTypeID=1Tue, 09 Feb 2016 12:03:13 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7a3738fb-3ea9-4a1b-873b-78e9e48496d5Susheel Nuguru<p>just adding link to older reply <a href="https://devzone.nordicsemi.com/question/1489/can-i-debug-ble-program/#reply-1504">here</a></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/44613?ContentTypeID=1Tue, 09 Feb 2016 11:46:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3d7c3e0e-335c-4fce-9a9e-eccc8c64fd9earmin<p>additional, it always happens if the breakpoint is in context of a s100 callback!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/44614?ContentTypeID=1Tue, 09 Feb 2016 11:30:21 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b05bfd94-2350-437f-8add-895849291ba6RK<p>Yes that&#39;s absolutely correct and discussed here quite often. If you break when the softdevice is running you get to look at the state of things at that point, but that&#39;s it, as soon as you try to step or re-start, the softdevice finds that it&#39;s missed many time critical events and aborts.</p> <p>You can set PRIMASK to block all interrupts before you try single stepping and that will let you step over a few instructions, but once you have stopped the softdevice and broken its timing, that&#39;s the end of that debug session.</p> <p>See the blog post from last week about Monitor Mode debugging with Segger for a different way to debug which helps somewhat.</p><div style="clear:both;"></div>